No presidential candidate has run a campaign as aggressively supportive of abortion as the one Barack Obama did this year. The fact that he won — and by a bigger margin than any Republican has managed in more than 20 years — suggests that the politics surrounding the issue has changed, to the disadvantage of pro-lifers.

Abortion has never been a top voting issue for most people. Among those people who do vote on abortion, however, pro-lifers have outnumbered pro-choicers. In 1988, ABC’s exit poll found that 33 percent of voters had considered abortion a “very important” issue in making their decision, and they favored George H. W. Bush over Michael Dukakis by a margin of 54 percent to 45 percent. The CBS exit poll that year found 7 percent of the voters saying that it was one of the issues that mattered most, and they had broken 65 percent to 33 percent for the pro-life Republican.

That pro-life advantage persisted in the exit polls of 1992, 1996, and 2000. In that last year, 14 percent of voters in the Los Angeles Times exit poll said abortion was a top issue, and they picked George W. Bush over Al Gore, 58 to 41 percent. The exit pollsters stopped asking the question after that election, but other polls have almost always found the same pattern. Gallup has concluded that the issue of abortion has won Republicans a net 2 percent of the total vote in every presidential election from 1996 until today, except for 2004, when it netted them 7 percent. The Polling Company, a conservative firm hired by the National Right to Life Committee (NRLC), found that 25 percent of voters in 2008 identified opposition to abortion as having affected their vote, compared with 9 percent who said support for legal abortion affected theirs.

Among the majority of voters not firmly committed to one side of the abortion debate, polls found, not surprisingly, ambivalence. Thus results depended heavily on the wording of questions. Asked whether the decision to abort should be between a woman and her doctor, a majority said yes; asked whether abortion should be illegal with exceptions for pregnancies that threaten the woman’s life or resulted from rape or incest, a majority also said yes. Even in the early 1990s, the period of strongest public support for the pro-choice position, Bill Clinton felt it necessary to pay respect to this ambivalence by saying that abortion should be “safe, legal, and rare.”

The majority seemed to be not only ambivalent about, but hostile to, the subject, unhappy when politicians brought it up. That sentiment imposed limits on both sides. It worked in favor of a status quo in which abortion is legal and common but not, usually, funded by taxpayers. It worked against rhetorical aggressiveness coming from either pro-life or pro-choice politicians.

In recent years the public as a whole seemed to be moving in a pro-life direction. Between 1994 and 2012, the percentage of Americans who told Gallup that abortion should be legal under “any” or “most” circumstances fell from 46 to 38 percent, while the percentage who said it should be legal in few or no circumstances rose from 51 to 59. Americans also became much more willing to describe themselves as “pro-life,” and less willing to describe themselves as “pro-choice.”

This year, Obama campaigned more or less as he would have in a country much more strongly and unequivocally pro-choice than these polls suggest. The Democratic platform no longer expresses the wish that abortion be “rare,” and the president and first lady have repeatedly said it should be an option for their daughters when they are older. The party’s convention in Charlotte at times resembled a NARAL conference.

A risky strategy, one might have thought; and I wrote as much in this space. When the election was over, though, Obama had won convincingly — and the pro-life advantage had been erased. The Polling Company’s post-election survey for the NRLC in 2012 found that the percentage of Americans who cast their presidential ballots against abortion, so to speak, held steady at 25, while the percentage who voted the other way jumped to 24.

The press has not noticed this sudden shift, because for the most part it didn’t recognize the existence of a pro-life advantage in the first place. Even those journalists who have noticed a shift have misunderstood it. John Judis, a perceptive liberal analyst, wrote in The New Republic soon after the election that Obama had been aided by “Democrats’ championing of abortion rights. The country was once evenly divided on this issue, but in this year’s exit polls, 59 percent of the electorate said that abortion should be legal in all or most cases. Those voters went overwhelmingly for Obama.”

Those numbers are not actually all that far off from the ones in the 2004 exit poll. Back then, 55 percent of voters thought abortion should be legal in most or all cases. (For some reason, polls that ask Americans whether abortion should be legal in “most cases” consistently yield larger results for the pro-choice side than ones that ask about “most circumstances.”) The modest difference appears to be entirely a function of the fact that more of the voters in 2012 were self-described liberals than in 2004 (25 percent vs. 21 percent). That change, in turn, probably reflects the increased Democratic edge in turning out voters at least as much as the growth of liberalism. In short, public opinion does not appear to have shifted substantially to the pro-choice side.

The media’s coverage of the 2012 elections cannot explain the shift in voting patterns any more than changes in public opinion can. That coverage was, to be sure, dismal. The Democratic platform called for taxpayer funding and endorsed a right to abortion without specifying what if any limits should be placed on it. The Republican platform endorsed a ban on abortion without specifying what if any exceptions it should have. The press obsessed about the Republican platform — which it described as calling for a ban on abortion even in the cases of rape and incest — and almost entirely ignored the ways the Democratic platform diverged from the views of moderate voters on the issue.

As a state senator, Obama opposed providing legal protection to pre-viable infants who survived attempted abortions. In 2008 the press bought every excuse the Obama campaign produced to minimize what he had done, no matter how easily disproven; in 2012 it largely ignored the issue as ancient history while reporting on Republican extremism.

The press has tilted heavily toward the pro-choice side of the abortion debate for as long as there has been one. That bias, however, has not kept pro-lifers from winning elections in the past, or from winning them in part because of the abortion issue.

What changed this year appears to be that pro-lifers gave their opponents, and journalists sympathetic to them, ammunition. Senate candidates Todd Akin and Richard Mourdock took an unpopular position — opposition to abortion in the cases of rape and incest — and expressed it in ways that drove their support down still further. Press attention to their remarks, the absurd intensity of which was quite predictable, highlighted the extent to which many pro-lifers are out of sync with public opinion.

The one Republican capable of countering this perception, Mitt Romney, campaigned on the assumption that saying anything about abortion was a dangerous distraction from explaining that unemployment was too high. His campaign took the same approach to Democratic charges that Republicans, by opposing Obama’s policy of forcing employers to offer coverage for contraceptives and abortion drugs, were waging a “war on women.” When the subject came up during a presidential debate, Romney said he favored contraceptive access and that Obama was distorting his position. He did not, however, explain why he opposed Obama’s policy or his approach to these issues generally. Other Republicans, panicked by the Akin and Mourdock media frenzies — and, before that, by the furor over Rush Limbaugh’s denunciation of a supporter of the Obama contraceptive policy as a “slut” — adopted the same tactic.

The Susan B. Anthony List, a pro-life group, accurately described these tactics in its own post-election analysis: “Anytime a GOP candidate was asked to respond to the ‘War on Women’ claims made by the other side, they ducked for cover and had a canned response simply saying that the Obama economy was bad for women.” Despite such evasions, Republicans came across as the more aggressive party on abortion — one that might well ban all abortions, but would not be candid about these plans. The effect appears to have been to convert soft pro-choicers into people who voted against what they saw as pro-life extremism.

The alternative was not for Republicans to place opposition to abortion front and center in their campaigns, something few Republican candidates have done (and no presidential candidate has ever done). It was to highlight Obama’s own out-of-the-mainstream positions. George W. Bush did this quite effectively in his debates with John Kerry.

Pro-life Republicans, even those who believe that in an ideal legal regime abortion would not be allowed in cases of rape and incest, might well also ponder whether it makes sense to speak of such theoretical positions as though they had any relevance to contemporary politics. Why not just say, “Any law to protect the unborn is going to have to include an exception for rape and incest, and banning abortion in those cases is no part of my agenda”? There is no reason a pro-lifer could not say these things in good conscience. Yet a few pro-life groups even ask candidates to pledge their support for an unattainably pure policy, to the detriment of their ability to advance feasible protections for unborn life.

The political condition of the pro-life cause is not by any means hopeless. Pro-life candidates did better in the Senate elections, for example, than Republican candidates did. Pro-life Republican Ted Cruz replaced moderate pro-choice Republican Kay Bailey Hutchison in Texas. A pro-life Democrat replaced a pro-life Republican in Indiana, and the reverse happened in Nebraska. Pro-choice Republicans lost seats to pro-choice Democrats in Maine and Massachusetts. The net result was that pro-lifers gained a seat even as Republicans lost two. That’s evidence that the abortion issue did not drag the party down.

The biggest political problems for pro-lifers remain what they have been for many years: They are in coalition with economic conservatives who have not found a way to translate their principles into a popular program, and they have not found a way to form a coalition with blacks and Hispanics who agree with them. Solving or mitigating those problems will require a massive effort not limited to the pro-life movement alone. In the meantime, pro-life politicians cannot afford to make avoidable mistakes.